Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding str...Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.展开更多
Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design o...Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consider the variable stiffness design optimization of typical non-perforated and perforated composite laminates with circular, square, and irregular holes, and systematically discuss the number of candidate discrete fiber laying angles, discrete fiber continuous filtering strategies, and filter radius on structural compliance, continuity, and manufacturability. The optimized discrete fiber angles of variable stiffness laminates are converted into continuous fiber laying paths using a streamlined process for continuous fiber additive manufacturing. Meanwhile, the optimized non-perforated and perforated MBB beams after discrete fiber continuous treatment, are manufactured using continuous fiber co-extrusion additive manufacturing technology to verify the effectiveness of the variable stiffness fiber optimization framework proposed in this paper.展开更多
On the basis ofa 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented, which is developed to model the delamination damage of composite laminates. In the method...On the basis ofa 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented, which is developed to model the delamination damage of composite laminates. In the method, the sublaminate elements are generated automatically when the delamination damage occurs or extends. Thus, the complex process and state of delamination damage can be simulated practically with high efficiency for both analysis and modeling. Based on the self-adapting delamination method, linear dynamic finite element damage analysis is performed to simulate the low-velocity impact damage process of three types of mixed woven composite laminates. Taking the frictional force among sublaminations during delaminating and the transverse normal stress into account, the analytical results are consistent with those of the experimental data.展开更多
Three types of Al/Al−27%Si laminated composites,each containing 22%Si,were fabricated via hot pressing and hot rolling.The microstructures,mechanical properties and thermo-physical properties of these composites were ...Three types of Al/Al−27%Si laminated composites,each containing 22%Si,were fabricated via hot pressing and hot rolling.The microstructures,mechanical properties and thermo-physical properties of these composites were investigated.The results demonstrated that the three laminated composites exhibited similar microstructural features,characterized by well-bonded interfaces between the Al layer and the Al−27%Si alloy layer.The tensile and flexural strengths of the composites were significantly higher than those of both Al−22%Si and Al−27%Si alloys.These strengths increased gradually with decreasing the layer thickness,reaching peak values of 222.5 and 407.4 MPa,respectively.Crack deflection was observed in the cross-sections of the bending fracture surfaces,which contributed to the enhanced strength and toughness.In terms of thermo-physical properties,the thermal conductivity of the composites was lower than that of Al−22%Si and Al−27%Si alloys.The minimum reductions in thermal conductivity were 6.8%and 0.9%for the T3 laminated composite,respectively.Additionally,the coefficient of thermal expansion of the composites was improved,exhibiting varying temperature-dependent behaviors.展开更多
Lightweight,high-strength,and heat-resistant protective structures have consistently been crucial for applications in extreme environments,such as aerospace,semiconductors,and nuclear power industries.Multilayered TC4...Lightweight,high-strength,and heat-resistant protective structures have consistently been crucial for applications in extreme environments,such as aerospace,semiconductors,and nuclear power industries.Multilayered TC4/TB8 titanium(Ti)laminates,inspired by theheterostructures of natural biological shells,were fabricated using a hybrid diffusion bonding-hot rolling process followed by an aging treatment,resulting in an architected micro structure.The laminate achieves an ultra-high yield stress of 1020 MPa and proper uniform elongation of 4.2%at 500℃.The TB8 layers with high-density nano-precipitates and dislocations act as hard zone,contributing to high strength.The TC4 layers,with their bimodal structure consisting of coarse and fine grains characterized by equiaxed and lamellar structures,experience more plastic strain than the TB8 layers.The hetero deformation associated with the detwinning ofαgrains in the TC4 layer induces toughening at high temperatures.展开更多
Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The tech...Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The techniques of FESEM/EDS,grazing incident beam X-ray diffraction(GIXRD),and electrochemical methods of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)were used to characterize the coatings.The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one.The corrosion performance of the specimens’cut edge was investigated using EIS after 1,8,and 12 h of immersion in a 3.5 wt.%NaCl solution.It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 h of immersion,with an estimated corrosion resistance of 5.64 kΩ·cm^(2),which was approximately 3 times higher than that of the unipolar coating.Notably,no signs of galvanic corrosion were observed in the LMCs,and only minor corrosion attacks were observed on the magnesium layer in some areas.展开更多
This study aims to investigate the propagation of harmonic waves in nonlocal magneto-electro-elastic(MEE)laminated composites with interface stress imperfections using an analytical approach.The pseudo-Stroh formulati...This study aims to investigate the propagation of harmonic waves in nonlocal magneto-electro-elastic(MEE)laminated composites with interface stress imperfections using an analytical approach.The pseudo-Stroh formulation and nonlocal theory proposed by Eringen were adopted to derive the propagator matrix for each layer.Both the propagator and interface matrices were formulated to determine the recursive fields.Subsequently,the dispersion equation was obtained by imposing traction-free and magneto-electric circuit open boundary conditions on the top and bottom surfaces of the plate.Dispersion curves,mode shapes,and natural frequencies were calculated for sandwich plates composed of BaTiO3 and CoFe2O4.Numerical simulations revealed that both interface stress and the nonlocal effect influenced the tuning of the dispersion curve and mode shape for the given layup.The nonlocal effect caused a significant decrease in the dispersion curves,particularly in the high-frequency regions.Additionally,compared to the nonlocal effect,the interface stress exerted a greater influence on the mode shapes.The generalized analytical framework developed in this study provides an effective tool for both the theoretical analysis and practical design of MEE composite laminates.展开更多
A partial-periodic model is proposed for predicting structural properties of composite laminate structures.The partial-periodic model contains periodic boundary conditions in one direction or two directions,and free b...A partial-periodic model is proposed for predicting structural properties of composite laminate structures.The partial-periodic model contains periodic boundary conditions in one direction or two directions,and free boundary condition in other directions.In the present study,partial-periodic model for composite laminate beam structures is particularly studied.Three-point bending experiments for laminate beam specimens with different laying parameters are firstly used to verify the present partial-periodic model.In addition,a detailed finite element method(FEM)model is also used to further quantitatively compare with the present partial-periodic model for composite laminate beams with different laying parameters.The results indicate that the proposed partial-periodic model is capable of providing accurate predictions in most cases.The computational time cost of the proposed partial-periodic model is much lower than that of the detailed FEM model as well.Convergence studies are also conducted for the present partial-periodic model with different model sizes and element sizes.It is suggested that the proposed partial-periodic model has the potential to be used as an accurate and time-saving tool for predicting the structural properties of composite laminate beam structures.展开更多
The remarkable mechanical properties exhibited by laminated structures have generated significant in-terest in the realm of additively manufactured laminated high-entropy alloys(HEAs).Despite this bur-geoning interest...The remarkable mechanical properties exhibited by laminated structures have generated significant in-terest in the realm of additively manufactured laminated high-entropy alloys(HEAs).Despite this bur-geoning interest,the nexus between process,structure,and properties within laminated HEAs remains largely uncharted.There is a vast space for investigating the effect of the typical heterogeneous interface on the macroscopic mechanical properties.This study focuses on the influence of the characteristic het-erogeneous interface on macroscopic mechanical properties of laminated HEAs,particularly anisotropy.Using the 3D-printed Fe_(50)Mn_(30)Co_(10)Cr_(10)-CoCrNi HEA as a model,we investigate the impact of interface geometry on mechanical characteristics.Tensile tests show that the reduced interface spacing increases yield strength.This laminated HEA displays significant anisotropy in strength and ductility,depending on the loading direction relative to the interface.Electron microscopic observations suggest that finer layer spacing enhances interface and dislocation strengthening,increasing yield strength.Anisotropic behaviors are confirmed to be mediated by interface orientation,explained in terms of deformation compatibility and crack development at the interface.This research offers fundamental insights into the relationship between heterogeneous interfaces and the mechanical properties in laminated HEAs.The knowledge is vital for designing,fabricating,and optimizing laminated HEAs through additive manufacturing,advancing their engineering applications.展开更多
This study developed a five-layer Mg alloy laminate(pure Mg/AZ31/AZ91/AZ31/pure Mg)through an innovative synergistic strategy involving Al-element gradient design,extrusion,and short-term annealing.Microstructural cha...This study developed a five-layer Mg alloy laminate(pure Mg/AZ31/AZ91/AZ31/pure Mg)through an innovative synergistic strategy involving Al-element gradient design,extrusion,and short-term annealing.Microstructural characterization revealed hierarchical heterogeneities in grain size,texture intensity,dislocation density,and precipitated phases,accompanied by the formation of annealing twinning in pure Mg layer—a phenomenon rarely documented in Mg alloys.Mechanical tests demonstrated significant strengthening effects in all annealed samples,particularly in the 300℃/30 min annealed sample,which achieved the optimal comprehensive mechanical properties.The enhanced strength originated from the synergistic interaction among element-diffusion-induced solid solution strengthening,nanoscale β-Mg_(17)Al_(12) precipitation,and hetero-deformation-induced(HDI)strengthening.This approach breaks the strength-ductility trade-off induced by traditional annealing processes,offering a new paradigm for designing high-performance Mg alloy laminates.展开更多
Laminated metal composites(LMCs)have widespread application prospects and are set to become indispensable in addressing modern engineering challenges owing to their capability of leveraging the synergy between differe...Laminated metal composites(LMCs)have widespread application prospects and are set to become indispensable in addressing modern engineering challenges owing to their capability of leveraging the synergy between different metals and tailoring performance by flexibly regulating the layered configuration.The plastic forming process,as a promising advanced manufacturing technology,has been increasingly adopted for the fabrication of LMC components due to its advantages of high material utilization rate,high production efficiency,and excellent mechanical properties of the product.This review delved into the research progress on the plastic-forming process of LMCs,including rolling,extrusion,spinning,etc.It outlined the forming principles,unique characteristics,bonding mechanisms,and the influence of key process parameters on deformation,microstructure,and property.This review focused on the heterogeneous deformation and interfacial regulation of LMCs,providing insights into the mechanisms of heterogeneous deformation,damage and fracture,and formation mechanisms of intermetallic compounds.It also delineated the experimental characterization and numerical modeling methods to elucidate the heterogeneous deformation behavior,as well as the approaches to evaluating and enhancing the performance of LMCs.Finally,the challenges and prospects of manufacturing high-performance LMCs by plastic forming process are orchestrated.展开更多
Mg/Al laminate with ZK60Mg and TiB2/6061Al as constitute layers was fabricated through the porthole die co-extrusion and hot rolling.The effects of rolling and roll temperatures on the microstructure,interfacial struc...Mg/Al laminate with ZK60Mg and TiB2/6061Al as constitute layers was fabricated through the porthole die co-extrusion and hot rolling.The effects of rolling and roll temperatures on the microstructure,interfacial structure,mechanical properties,and crack propagation paths were studied.The results show that the intermetallic compounds layer shows an intermittent form.The strong strain/dislocation hardening ability of Mg/Al laminate is attributed to the coupled effects of interlocking Al/βinterface,strain gradient,andβlayer with nanotwins and stacking faults.The complex dislocation structures such as network,loop,and array are found in the Al layer.Dislocation slip is the main deformation mode of the Al layer,while dislocation slip and dynamic recrystallization are the main deformation modes of the Mg layer.As roll temperature increases,prismatic〈a〉slip replaces the basal〈a〉slip as the most important slip mode.At a rolling temperature of 400℃ and a roll temperature of 150℃,an optimal synergy of mechanical properties is achieved,with ultimate tensile strength,shear strength,and elongation of 262.1 MPa,36.4 MPa,and 18.1%,respectively.As the rolling temperature increases,the fracture mode of Mg/Al laminate changes from discontinuous plastic shrinkage to transverse and longitudinal cracks.With increasing the roll temperature,the through cracks tend to form,indicating the plasticity and bonding quality of Mg/Al laminate are effectively enhanced.展开更多
Heterogeneous laminated structure(HLS)design offers new opportunities to enhance the mechanical performance of high-entropy alloys(HEAs)through synergistic effects from heterogeneity.However,it remains challenging to ...Heterogeneous laminated structure(HLS)design offers new opportunities to enhance the mechanical performance of high-entropy alloys(HEAs)through synergistic effects from heterogeneity.However,it remains challenging to introduce the HLS into HEAs via severe plastic deformation due to their strong work-hardening capacity.In this study,a specially designed multi-level HLS,characterized by alterna-tively stacked micro-grained soft CoCrFeNi layers and nanostructured ultra-hard Al_(0.3)CoCrFeNi layers con-taining a three-phase microstructure(composed of nanograined face-centered cubic matrix,(Al,Ni)-rich B2 precipitates,and Cr-richσprecipitates),is controllably introduced into FCC HEAs via a conventional thermo-mechanical processing involving hot-pressing,cold-rolling,and annealing.Meanwhile,thermo-mechanical processing induces Al element diffusion across the layer interface,resulting in the formation of an interfacial transition layer and the establishment of a strong interface bonding between the neigh-boring CoCrFeNi and Al_(0.3)CoCrFeNi layers.As a result,the multi-level HLSed CoCrFeNi/Al_(0.3)CoCrFeNi com-posite exhibits a yield strength as high as 1127±25.4 MPa while maintaining a large fracture elongation(up to(26.3±2.4)%).Such an excellent strength-ductility synergy surpasses that of most previously reported high-performance monolithic bulk CoCrFeNi and Al_(0.3)CoCrFeNi HEAs prepared through care-ful chemical composition optimization and/or thermo-mechanical processing.Strong hetero-deformation induced strengthening benefited from the apparent microstructural/microhardness difference and the strong interface bonding between the neighbouring CoCrFeNi and Al03CoCrFeNi layers,together with si-multaneous activation of multiple strain hardening mechanisms containing mechanical twinning,stack-ing faults and precipitation strengthening,is responsible for the excellent strength-ductility combination.This multi-level HLS and its fabrication strategy provide an enlightening way to develop strong and duc-tile HEAs and can also be applied to high-performance designs of other metallic materials.展开更多
In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ignored.Interestingly,by combining experiment and phase-field crystal simu...In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ignored.Interestingly,by combining experiment and phase-field crystal simulation,we found that the micrometer Al_(3)Ti particles in the diffusion layer play the role of crack deflection and passivation,which is attributed to the lattice distortion induced by Al_(3)Ti consumes the energy of the crack in extension.In addition,it is found that the growth process of Al_(3)Ti is divided into two stages:nucleation stage and growth stage.Compared with the growth stage,the Al_(3)Ti grains in the nucleation stage are finer in the growth layer.Finer grains show better crack deflection and avoid stress concentration.展开更多
Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investiga...Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investigated.The results revealed that a uniform Al/Cu interface with excellent bonding quality was achieved.The thickness of intermetallic compounds(IMCs)reached 33.88μm after sintering at 620℃for 2 h,whereas it was only 14.88μm when sintered at 600℃for 1 h.AlCu phase was developed through the reaction between Al4Cu9 and Al2Cu with prolonging sintering time,and an amorphous oxide strip formed at AlCu/Al4Cu9 interface.Both the grain morphology and interfacial structure affected the tensile strength of Al/Cu laminate,whereas the mode of tensile fracture strongly relied on the interfacial bonding strength.The highest tensile strength of 151.1 MPa and bonding strength of 93.7 MPa were achieved after sintering at 600℃for 1 h.展开更多
Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FML...Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.展开更多
The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The diffe...The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The difference of mechanical properties between the Cu and 1010 steel causes different thickness reductions,percentage spread,and cladding ratios.The formation of strong texture induces larger strength of the rolled samples,and as the volume fraction of 1010 steel is larger in Route-A,its strength is consistently greater than that in Route-B.The obstruction of interface to crystal and dislocation slip results in the formation of interface distortion,inducing dislocation density gradient when the rolling reduction is low in Route-A.The slip planes of the Cu and 1010 steel are more prone to suffer the normal strain,while the shear strain of other crystal planes is obviously larger than the normal strain under rolling load near the interface.展开更多
This research investigates the behavior of sandwich glued laminated bamboo(Glubam)structures with a core formed by biodegradable plastic fibers,specifically polylactic acid(PLA),fabricated using 3D printing technology...This research investigates the behavior of sandwich glued laminated bamboo(Glubam)structures with a core formed by biodegradable plastic fibers,specifically polylactic acid(PLA),fabricated using 3D printing technology.The influence of various fiber printing orientations(0°and 45/135°)on tensile and compressive properties was investigated.The experimental results indicated that polylactic acid with calcium carbonate(PLA+)printed unidirectionally and aligned with the loading direction(0°)exhibits superior tensile and compressive strengths compared to specimens printed bidirectionally at 45/135°.Furthermore,the effect of additives on bioplastics of carbon fiber(PLA-CF)and glass fiber(PLA-GF)additives in PLA-based composites was evaluated in comparison with PLA+specimens.The finding indicated that PLA+has a higher strength-to-cost ratio compared to PLA-CF and PLA-GF.Therefore,unidirectionally printed PLA+was selected as the core material in two geometries:honeycomb and honeycomb lattice.These cores were sandwiched between Glubam panels on the top and bottom surfaces of the structures.Flexural performance was evaluated through four-point bending tests,which revealed that sandwich structures with a honeycomb core achieved a flexural strength-to-weight ratio 56.51%higher than those with a honeycomb lattice core.A parametric study using the finite element model was conducted to evaluate the effect of core scale,cross-sectional depth,Glubamthickness,core depth,and the number of honeycomb elements.The results showed that reducing the Glubam thickness while increasing the 3D-printed core depth significantly improved the flexural performance of honeycomb sandwich structures.Notably,reduced Glubam panel thickness coupled with increased core depth enhanced their flexural performance.展开更多
Source rocks(shales) exhibit different geometric pore types and considerable anisotropy caused by the preferential orientation of the clay and kerogen layers,which is not accounted for in classical rockphysics models....Source rocks(shales) exhibit different geometric pore types and considerable anisotropy caused by the preferential orientation of the clay and kerogen layers,which is not accounted for in classical rockphysics models.Pore geometry can be effectively studied through the aspect ratio,and in this study,we use the aspect ratio to characterize different pore geometries.Then,we consider a pore connectivity index as well as a lamination index associated with these orientations.An inclusion-based theory(differential effective medium and self-consistent approximation) and the Brown-Korringa equations are used in the modeling approach.The results show that the indices as well as the aspect ratio of the connected pores significantly affect the elastic properties.We propose an inversion method to invert these three parameters simultaneously from experimental vertical P-and S-wave velocities using a global optimization algorithm.The method is applied to well log and seismic data from the Longmaxi shale reservoir in southwest China to verify its pre dictive ability.展开更多
Copper matrix composites prepared via traditional methods face mechanical property and electrical conductivity trade-off problems.In this study,TiB_(2)/Cu−Cu heterogeneous laminated composites with submicron lamellar ...Copper matrix composites prepared via traditional methods face mechanical property and electrical conductivity trade-off problems.In this study,TiB_(2)/Cu−Cu heterogeneous laminated composites with submicron lamellar thicknesses were prepared via flake powder metallurgy(FPM)using gas-atomized in situ composite powders as raw material.By thermal mismatch strengthening,and the geometrically necessary dislocations(GNDs)generated by mechanically incompatible deformation between adjacent heterogeneous lamellae and their interaction with statistically stored dislocations(SSDs),the as-prepared TiB_(2)/Cu−Cu submicron laminated composites(SLCs)exhibit significantly enhanced mechanical properties.At the same time,the interaction and propagation of multimode cracks provide extrinsic toughening for SLCs.The pure Cu lamellae with low density grain boundaries and dislocations and no TiB_(2)particles provide a channel with little electron scattering for the rapid transport of carriers,thereby ensuring high electrical conductivity.展开更多
基金supported by the National Key R&D Program of China (No. 2018YFA0707300)the National Natural Science Foundation of China (No. 52374376)the Introduction Plan for High end Foreign Experts, China (No. G2023105001L)。
文摘Titanium plates with a Ti−O solid solution surface-hardened layer were cold roll-bonded with 304 stainless steel plates with high work hardening rates.The evolution and mechanisms affecting the interfacial bonding strength in titanium/stainless steel laminated composites were investigated.Results indicate that the hardened layer reduces the interfacial bonding strength from over 261 MPa to less than 204 MPa.During the cold roll-bonding process,the hardened layer fractures,leading to the formation of multi-scale cracks that are difficult for the stainless steel to fill.This not only hinders the development of an interlocking interface but also leads to the presence of numerous microcracks and hardened blocks along the nearly straight interface,consequently weakening the interfacial bonding strength.In metals with high work hardening rates,the conventional approach of enhancing interface interlocking and improving interfacial bonding strength by using a surface-hardened layer becomes less effective.
基金supports for this research were provided by the National Natural Science Foundation of China(No.12272301,12002278,U1906233)the Guangdong Basic and Applied Basic Research Foundation,China(Nos.2023A1515011970,2024A1515010256)+1 种基金the Dalian City Supports Innovation and Entrepreneurship Projects for High-Level Talents,China(2021RD16)the Key R&D Project of CSCEC,China(No.CSCEC-2020-Z-4).
文摘Fiber-reinforced composites are an ideal material for the lightweight design of aerospace structures. Especially in recent years, with the rapid development of composite additive manufacturing technology, the design optimization of variable stiffness of fiber-reinforced composite laminates has attracted widespread attention from scholars and industry. In these aerospace composite structures, numerous cutout panels and shells serve as access points for maintaining electrical, fuel, and hydraulic systems. The traditional fiber-reinforced composite laminate subtractive drilling manufacturing inevitably faces the problems of interlayer delamination, fiber fracture, and burr of the laminate. Continuous fiber additive manufacturing technology offers the potential for integrated design optimization and manufacturing with high structural performance. Considering the integration of design and manufacturability in continuous fiber additive manufacturing, the paper proposes linear and nonlinear filtering strategies based on the Normal Distribution Fiber Optimization (NDFO) material interpolation scheme to overcome the challenge of discrete fiber optimization results, which are difficult to apply directly to continuous fiber additive manufacturing. With minimizing structural compliance as the objective function, the proposed approach provides a strategy to achieve continuity of discrete fiber paths in the variable stiffness design optimization of composite laminates with regular and irregular holes. In the variable stiffness design optimization model, the number of candidate fiber laying angles in the NDFO material interpolation scheme is considered as design variable. The sensitivity information of structural compliance with respect to the number of candidate fiber laying angles is obtained using the analytical sensitivity analysis method. Based on the proposed variable stiffness design optimization method for complex perforated composite laminates, the numerical examples consider the variable stiffness design optimization of typical non-perforated and perforated composite laminates with circular, square, and irregular holes, and systematically discuss the number of candidate discrete fiber laying angles, discrete fiber continuous filtering strategies, and filter radius on structural compliance, continuity, and manufacturability. The optimized discrete fiber angles of variable stiffness laminates are converted into continuous fiber laying paths using a streamlined process for continuous fiber additive manufacturing. Meanwhile, the optimized non-perforated and perforated MBB beams after discrete fiber continuous treatment, are manufactured using continuous fiber co-extrusion additive manufacturing technology to verify the effectiveness of the variable stiffness fiber optimization framework proposed in this paper.
基金National Natural Science Foundation of China (50073002)
文摘On the basis ofa 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented, which is developed to model the delamination damage of composite laminates. In the method, the sublaminate elements are generated automatically when the delamination damage occurs or extends. Thus, the complex process and state of delamination damage can be simulated practically with high efficiency for both analysis and modeling. Based on the self-adapting delamination method, linear dynamic finite element damage analysis is performed to simulate the low-velocity impact damage process of three types of mixed woven composite laminates. Taking the frictional force among sublaminations during delaminating and the transverse normal stress into account, the analytical results are consistent with those of the experimental data.
基金supported by the National Natural Science Foundation of China(No.52274369)the National Key Laboratory of Science and Technology on High-strength Structural Materials,China(No.623020034).
文摘Three types of Al/Al−27%Si laminated composites,each containing 22%Si,were fabricated via hot pressing and hot rolling.The microstructures,mechanical properties and thermo-physical properties of these composites were investigated.The results demonstrated that the three laminated composites exhibited similar microstructural features,characterized by well-bonded interfaces between the Al layer and the Al−27%Si alloy layer.The tensile and flexural strengths of the composites were significantly higher than those of both Al−22%Si and Al−27%Si alloys.These strengths increased gradually with decreasing the layer thickness,reaching peak values of 222.5 and 407.4 MPa,respectively.Crack deflection was observed in the cross-sections of the bending fracture surfaces,which contributed to the enhanced strength and toughness.In terms of thermo-physical properties,the thermal conductivity of the composites was lower than that of Al−22%Si and Al−27%Si alloys.The minimum reductions in thermal conductivity were 6.8%and 0.9%for the T3 laminated composite,respectively.Additionally,the coefficient of thermal expansion of the composites was improved,exhibiting varying temperature-dependent behaviors.
基金financially supported by the Natural Science Foundation of Changsha,China(No.kq2402015)the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(Nos.NRF-2021R1A2C3006662 and NRF-2022R1A5A1030054)supported by Brain Pool Program through the NRF of Korea,funded by the Ministry of Science and ICT(No.NRF-RS_(2)02300263999)
文摘Lightweight,high-strength,and heat-resistant protective structures have consistently been crucial for applications in extreme environments,such as aerospace,semiconductors,and nuclear power industries.Multilayered TC4/TB8 titanium(Ti)laminates,inspired by theheterostructures of natural biological shells,were fabricated using a hybrid diffusion bonding-hot rolling process followed by an aging treatment,resulting in an architected micro structure.The laminate achieves an ultra-high yield stress of 1020 MPa and proper uniform elongation of 4.2%at 500℃.The TB8 layers with high-density nano-precipitates and dislocations act as hard zone,contributing to high strength.The TC4 layers,with their bimodal structure consisting of coarse and fine grains characterized by equiaxed and lamellar structures,experience more plastic strain than the TB8 layers.The hetero deformation associated with the detwinning ofαgrains in the TC4 layer induces toughening at high temperatures.
文摘Plasma electrolytic oxidation(PEO)coatings were prepared on Al−Mg laminated macro composites(LMCs)using both unipolar and bipolar waveforms in an appropriate electrolyte for both aluminum and magnesium alloys.The techniques of FESEM/EDS,grazing incident beam X-ray diffraction(GIXRD),and electrochemical methods of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS)were used to characterize the coatings.The results revealed that the coatings produced using the bipolar waveform exhibited lower porosity and higher thickness than those produced using the unipolar one.The corrosion performance of the specimens’cut edge was investigated using EIS after 1,8,and 12 h of immersion in a 3.5 wt.%NaCl solution.It was observed that the coating produced using the bipolar waveform demonstrated the highest corrosion resistance after 12 h of immersion,with an estimated corrosion resistance of 5.64 kΩ·cm^(2),which was approximately 3 times higher than that of the unipolar coating.Notably,no signs of galvanic corrosion were observed in the LMCs,and only minor corrosion attacks were observed on the magnesium layer in some areas.
基金supported by the Ministry of Science and Technology Taiwan under Grant No.MOST 109-2628-E-009-002-MY3.
文摘This study aims to investigate the propagation of harmonic waves in nonlocal magneto-electro-elastic(MEE)laminated composites with interface stress imperfections using an analytical approach.The pseudo-Stroh formulation and nonlocal theory proposed by Eringen were adopted to derive the propagator matrix for each layer.Both the propagator and interface matrices were formulated to determine the recursive fields.Subsequently,the dispersion equation was obtained by imposing traction-free and magneto-electric circuit open boundary conditions on the top and bottom surfaces of the plate.Dispersion curves,mode shapes,and natural frequencies were calculated for sandwich plates composed of BaTiO3 and CoFe2O4.Numerical simulations revealed that both interface stress and the nonlocal effect influenced the tuning of the dispersion curve and mode shape for the given layup.The nonlocal effect caused a significant decrease in the dispersion curves,particularly in the high-frequency regions.Additionally,compared to the nonlocal effect,the interface stress exerted a greater influence on the mode shapes.The generalized analytical framework developed in this study provides an effective tool for both the theoretical analysis and practical design of MEE composite laminates.
基金financial support from the National Key Research and Development Plan(2022YFB3707700)the National Natural Science Foundation of China(11872138 and 12172074)+1 种基金the Liaoning Revitalization Talents Program(XLYC2001003)the Dalian Excellent Young Science and Technology Talent Program(2023RY025).
文摘A partial-periodic model is proposed for predicting structural properties of composite laminate structures.The partial-periodic model contains periodic boundary conditions in one direction or two directions,and free boundary condition in other directions.In the present study,partial-periodic model for composite laminate beam structures is particularly studied.Three-point bending experiments for laminate beam specimens with different laying parameters are firstly used to verify the present partial-periodic model.In addition,a detailed finite element method(FEM)model is also used to further quantitatively compare with the present partial-periodic model for composite laminate beams with different laying parameters.The results indicate that the proposed partial-periodic model is capable of providing accurate predictions in most cases.The computational time cost of the proposed partial-periodic model is much lower than that of the detailed FEM model as well.Convergence studies are also conducted for the present partial-periodic model with different model sizes and element sizes.It is suggested that the proposed partial-periodic model has the potential to be used as an accurate and time-saving tool for predicting the structural properties of composite laminate beam structures.
基金supported by the National Natural Science Foundation of China(No.12272392 and 11790292)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040303)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2022020).
文摘The remarkable mechanical properties exhibited by laminated structures have generated significant in-terest in the realm of additively manufactured laminated high-entropy alloys(HEAs).Despite this bur-geoning interest,the nexus between process,structure,and properties within laminated HEAs remains largely uncharted.There is a vast space for investigating the effect of the typical heterogeneous interface on the macroscopic mechanical properties.This study focuses on the influence of the characteristic het-erogeneous interface on macroscopic mechanical properties of laminated HEAs,particularly anisotropy.Using the 3D-printed Fe_(50)Mn_(30)Co_(10)Cr_(10)-CoCrNi HEA as a model,we investigate the impact of interface geometry on mechanical characteristics.Tensile tests show that the reduced interface spacing increases yield strength.This laminated HEA displays significant anisotropy in strength and ductility,depending on the loading direction relative to the interface.Electron microscopic observations suggest that finer layer spacing enhances interface and dislocation strengthening,increasing yield strength.Anisotropic behaviors are confirmed to be mediated by interface orientation,explained in terms of deformation compatibility and crack development at the interface.This research offers fundamental insights into the relationship between heterogeneous interfaces and the mechanical properties in laminated HEAs.The knowledge is vital for designing,fabricating,and optimizing laminated HEAs through additive manufacturing,advancing their engineering applications.
基金supported by the Joint Foundation of Hubei Province(No.2024AFD113)Hubei Provincial Department of Education Science and Technology Plan Project(No.D20231804)+3 种基金Natural Science Fund Project of Hubei Province(No.2024AFD099)Hubei Province Technological Innovation Special Major Project(No.2023BEB015)Doctoral Scientific Research Foundation of Hubei University of Automotive Technology(No.BK202336)Hubei University of Automotive Technology 2024 Annual Unveiling the List and Taking Command(ULTC)Projects.
文摘This study developed a five-layer Mg alloy laminate(pure Mg/AZ31/AZ91/AZ31/pure Mg)through an innovative synergistic strategy involving Al-element gradient design,extrusion,and short-term annealing.Microstructural characterization revealed hierarchical heterogeneities in grain size,texture intensity,dislocation density,and precipitated phases,accompanied by the formation of annealing twinning in pure Mg layer—a phenomenon rarely documented in Mg alloys.Mechanical tests demonstrated significant strengthening effects in all annealed samples,particularly in the 300℃/30 min annealed sample,which achieved the optimal comprehensive mechanical properties.The enhanced strength originated from the synergistic interaction among element-diffusion-induced solid solution strengthening,nanoscale β-Mg_(17)Al_(12) precipitation,and hetero-deformation-induced(HDI)strengthening.This approach breaks the strength-ductility trade-off induced by traditional annealing processes,offering a new paradigm for designing high-performance Mg alloy laminates.
基金supported by the National Natural Science Foundation of China(Grant Nos.52305361,52105337,52475354,and 52090043)the BK21 Four program(SNU Materials Education/Research Division for Creative Global Leaders)+1 种基金the China Postdoctoral Science Foundation(Grant No.2023M741245),and the National Key Research and Development Program of China(Grant No.2022YFB3706903)support from the Ko-rean Ministry of Trade,Industry and Energy(MOTIE,Korea)(Grant No.20022438).
文摘Laminated metal composites(LMCs)have widespread application prospects and are set to become indispensable in addressing modern engineering challenges owing to their capability of leveraging the synergy between different metals and tailoring performance by flexibly regulating the layered configuration.The plastic forming process,as a promising advanced manufacturing technology,has been increasingly adopted for the fabrication of LMC components due to its advantages of high material utilization rate,high production efficiency,and excellent mechanical properties of the product.This review delved into the research progress on the plastic-forming process of LMCs,including rolling,extrusion,spinning,etc.It outlined the forming principles,unique characteristics,bonding mechanisms,and the influence of key process parameters on deformation,microstructure,and property.This review focused on the heterogeneous deformation and interfacial regulation of LMCs,providing insights into the mechanisms of heterogeneous deformation,damage and fracture,and formation mechanisms of intermetallic compounds.It also delineated the experimental characterization and numerical modeling methods to elucidate the heterogeneous deformation behavior,as well as the approaches to evaluating and enhancing the performance of LMCs.Finally,the challenges and prospects of manufacturing high-performance LMCs by plastic forming process are orchestrated.
基金supported by the National Natural Science Foundation of China(Nos.52175338 and 52222510)Science Fund for Distinguished Young Scholars of Shandong Province(No.ZR2021JQ21)+1 种基金Key Research and Development Program of Shandong Province(No.2021ZLGX01)The Excellent Young Team Project of Central Universities(No.2023QNTD002).
文摘Mg/Al laminate with ZK60Mg and TiB2/6061Al as constitute layers was fabricated through the porthole die co-extrusion and hot rolling.The effects of rolling and roll temperatures on the microstructure,interfacial structure,mechanical properties,and crack propagation paths were studied.The results show that the intermetallic compounds layer shows an intermittent form.The strong strain/dislocation hardening ability of Mg/Al laminate is attributed to the coupled effects of interlocking Al/βinterface,strain gradient,andβlayer with nanotwins and stacking faults.The complex dislocation structures such as network,loop,and array are found in the Al layer.Dislocation slip is the main deformation mode of the Al layer,while dislocation slip and dynamic recrystallization are the main deformation modes of the Mg layer.As roll temperature increases,prismatic〈a〉slip replaces the basal〈a〉slip as the most important slip mode.At a rolling temperature of 400℃ and a roll temperature of 150℃,an optimal synergy of mechanical properties is achieved,with ultimate tensile strength,shear strength,and elongation of 262.1 MPa,36.4 MPa,and 18.1%,respectively.As the rolling temperature increases,the fracture mode of Mg/Al laminate changes from discontinuous plastic shrinkage to transverse and longitudinal cracks.With increasing the roll temperature,the through cracks tend to form,indicating the plasticity and bonding quality of Mg/Al laminate are effectively enhanced.
基金supported by the National Natural Science Foundation of China(No.52361021)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(No.20232BCJ23001)+1 种基金the Jiangxi Provincial Natural Science Foundation(No.20232ACB214003)the Jiangxi Province Major Science&Technology Research&Development Project(No.20223AAG01009).
文摘Heterogeneous laminated structure(HLS)design offers new opportunities to enhance the mechanical performance of high-entropy alloys(HEAs)through synergistic effects from heterogeneity.However,it remains challenging to introduce the HLS into HEAs via severe plastic deformation due to their strong work-hardening capacity.In this study,a specially designed multi-level HLS,characterized by alterna-tively stacked micro-grained soft CoCrFeNi layers and nanostructured ultra-hard Al_(0.3)CoCrFeNi layers con-taining a three-phase microstructure(composed of nanograined face-centered cubic matrix,(Al,Ni)-rich B2 precipitates,and Cr-richσprecipitates),is controllably introduced into FCC HEAs via a conventional thermo-mechanical processing involving hot-pressing,cold-rolling,and annealing.Meanwhile,thermo-mechanical processing induces Al element diffusion across the layer interface,resulting in the formation of an interfacial transition layer and the establishment of a strong interface bonding between the neigh-boring CoCrFeNi and Al_(0.3)CoCrFeNi layers.As a result,the multi-level HLSed CoCrFeNi/Al_(0.3)CoCrFeNi com-posite exhibits a yield strength as high as 1127±25.4 MPa while maintaining a large fracture elongation(up to(26.3±2.4)%).Such an excellent strength-ductility synergy surpasses that of most previously reported high-performance monolithic bulk CoCrFeNi and Al_(0.3)CoCrFeNi HEAs prepared through care-ful chemical composition optimization and/or thermo-mechanical processing.Strong hetero-deformation induced strengthening benefited from the apparent microstructural/microhardness difference and the strong interface bonding between the neighbouring CoCrFeNi and Al03CoCrFeNi layers,together with si-multaneous activation of multiple strain hardening mechanisms containing mechanical twinning,stack-ing faults and precipitation strengthening,is responsible for the excellent strength-ductility combination.This multi-level HLS and its fabrication strategy provide an enlightening way to develop strong and duc-tile HEAs and can also be applied to high-performance designs of other metallic materials.
基金supported by the National Natural Science Foundation of China(Nos.52375394,52074246,52275390,52205429,52201146)the National Defense Basic Scientific Research Program of China(JCKY2020408B002)the Key Research and Development Program of Shanxi Province(202102050201011,202202050201014).
文摘In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ignored.Interestingly,by combining experiment and phase-field crystal simulation,we found that the micrometer Al_(3)Ti particles in the diffusion layer play the role of crack deflection and passivation,which is attributed to the lattice distortion induced by Al_(3)Ti consumes the energy of the crack in extension.In addition,it is found that the growth process of Al_(3)Ti is divided into two stages:nucleation stage and growth stage.Compared with the growth stage,the Al_(3)Ti grains in the nucleation stage are finer in the growth layer.Finer grains show better crack deflection and avoid stress concentration.
基金the financial support from the National Natural Science Foundation of China(Nos.51875317,52222510)Key Research and Development Program of Shandong Province,China(No.2021ZLGX01)。
文摘Al/Cu laminate composite was fabricated based on hot press sintering using Cu sheet and Al powders as raw materials.The effects of sintering parameters on interfacial structure and mechanical properties were investigated.The results revealed that a uniform Al/Cu interface with excellent bonding quality was achieved.The thickness of intermetallic compounds(IMCs)reached 33.88μm after sintering at 620℃for 2 h,whereas it was only 14.88μm when sintered at 600℃for 1 h.AlCu phase was developed through the reaction between Al4Cu9 and Al2Cu with prolonging sintering time,and an amorphous oxide strip formed at AlCu/Al4Cu9 interface.Both the grain morphology and interfacial structure affected the tensile strength of Al/Cu laminate,whereas the mode of tensile fracture strongly relied on the interfacial bonding strength.The highest tensile strength of 151.1 MPa and bonding strength of 93.7 MPa were achieved after sintering at 600℃for 1 h.
基金supported by the National Natural Science Fund of China(Nos.52005153,12227801,32300666,12072005,U23A2607)the Tianjin"Project+Team"Key Training Program,China(No.XC202052)+4 种基金the Key Program of Research and Development of Hebei Province,China(Nos.202030507040009,23311812D)the Natural Science Foundation of Hebei Province,China(No.E2023202183)the Project of High-Level Team Construction Introduction of Hebei Province,China(No.244A7620D)the Research Cooperation Project of Universities Stationed in Hebei Province and Shijiazhuang City,China(No.241080114A)Hebei Province Military-Civilian Integration Science and Technology Innovation Project,China(No.SJMYF2022X15)。
文摘Fiber Metal Laminates(FMLs),as high-performance composite materials,demonstrate exceptional potential in a wide range of applications,such as aeronautical and astronautical industries.However,the traditional cured FMLs possess complex interlayer stresses and low forming limits,restricting further promotion and application of FMLs.Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process;however,the formation mechanism and response are not clear.This paper presents the Forming Limit Diagram(FLD)of low-constraint GLARE(glass fiber reinforced aluminum laminates)based on the forming limit test,and compares it with the conventionally cured laminates to evaluate the differences in the forming limit.In addition,combined with the analysis of failure mechanism and micro-deformation mechanism of specimens,the influence of different temperatures(20–80℃)and forming states(width)on the deformation performance of laminates is further explored.The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature,the forming limit initially increases with the increase of width,then followed by a gradual decrease,and the maximum principal strain of low-constraint laminates is increased by 29% at 80℃ compared to 20℃.The cured laminate has a principal strain range of 0–0.02,while the low-constraint laminates have a principal strain range of 0.03–0.14.Compared with cured laminates,low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage,which enhances their formability.This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.
基金the National Key Research and Development Program of China(No.2018YFE0306103)the National Natural Science Foundation of China(No.52071050)+1 种基金the Science and Technology Innovation Project of Ningbo,China(No.2021Z032)the Program of China Scholarships Council(No.202106060148).
文摘The Cu/1010 steel bimetal laminated composites(BLCs)were rolled to different thicknesses to investigate the effect of rolling direction and reduction on the microstructure evolution and mechanical properties.The difference of mechanical properties between the Cu and 1010 steel causes different thickness reductions,percentage spread,and cladding ratios.The formation of strong texture induces larger strength of the rolled samples,and as the volume fraction of 1010 steel is larger in Route-A,its strength is consistently greater than that in Route-B.The obstruction of interface to crystal and dislocation slip results in the formation of interface distortion,inducing dislocation density gradient when the rolling reduction is low in Route-A.The slip planes of the Cu and 1010 steel are more prone to suffer the normal strain,while the shear strain of other crystal planes is obviously larger than the normal strain under rolling load near the interface.
基金provided by the Thailand Science Research and Innovation(TSRI)through the Basic Research Fund,Fiscal Year 2026,for the project“Numerical Modeling and Structural Analysis of Composite Sections Built-up from Local Timber inThailand”.
文摘This research investigates the behavior of sandwich glued laminated bamboo(Glubam)structures with a core formed by biodegradable plastic fibers,specifically polylactic acid(PLA),fabricated using 3D printing technology.The influence of various fiber printing orientations(0°and 45/135°)on tensile and compressive properties was investigated.The experimental results indicated that polylactic acid with calcium carbonate(PLA+)printed unidirectionally and aligned with the loading direction(0°)exhibits superior tensile and compressive strengths compared to specimens printed bidirectionally at 45/135°.Furthermore,the effect of additives on bioplastics of carbon fiber(PLA-CF)and glass fiber(PLA-GF)additives in PLA-based composites was evaluated in comparison with PLA+specimens.The finding indicated that PLA+has a higher strength-to-cost ratio compared to PLA-CF and PLA-GF.Therefore,unidirectionally printed PLA+was selected as the core material in two geometries:honeycomb and honeycomb lattice.These cores were sandwiched between Glubam panels on the top and bottom surfaces of the structures.Flexural performance was evaluated through four-point bending tests,which revealed that sandwich structures with a honeycomb core achieved a flexural strength-to-weight ratio 56.51%higher than those with a honeycomb lattice core.A parametric study using the finite element model was conducted to evaluate the effect of core scale,cross-sectional depth,Glubamthickness,core depth,and the number of honeycomb elements.The results showed that reducing the Glubam thickness while increasing the 3D-printed core depth significantly improved the flexural performance of honeycomb sandwich structures.Notably,reduced Glubam panel thickness coupled with increased core depth enhanced their flexural performance.
基金funded by the National Natural Science Foundation of China (No. 42374128)by the Fundamental Research Funds for the Central Universities (No. B240201110)。
文摘Source rocks(shales) exhibit different geometric pore types and considerable anisotropy caused by the preferential orientation of the clay and kerogen layers,which is not accounted for in classical rockphysics models.Pore geometry can be effectively studied through the aspect ratio,and in this study,we use the aspect ratio to characterize different pore geometries.Then,we consider a pore connectivity index as well as a lamination index associated with these orientations.An inclusion-based theory(differential effective medium and self-consistent approximation) and the Brown-Korringa equations are used in the modeling approach.The results show that the indices as well as the aspect ratio of the connected pores significantly affect the elastic properties.We propose an inversion method to invert these three parameters simultaneously from experimental vertical P-and S-wave velocities using a global optimization algorithm.The method is applied to well log and seismic data from the Longmaxi shale reservoir in southwest China to verify its pre dictive ability.
基金supported by the National Natural Science Foundation of China(Nos.52127802,52322409,52271137)the Scientific Research Program of Education Department of Shaanxi Province,China(No.22JY050)the Science and Technology Project of Xi’an,China(No.2021SFGX0004).
文摘Copper matrix composites prepared via traditional methods face mechanical property and electrical conductivity trade-off problems.In this study,TiB_(2)/Cu−Cu heterogeneous laminated composites with submicron lamellar thicknesses were prepared via flake powder metallurgy(FPM)using gas-atomized in situ composite powders as raw material.By thermal mismatch strengthening,and the geometrically necessary dislocations(GNDs)generated by mechanically incompatible deformation between adjacent heterogeneous lamellae and their interaction with statistically stored dislocations(SSDs),the as-prepared TiB_(2)/Cu−Cu submicron laminated composites(SLCs)exhibit significantly enhanced mechanical properties.At the same time,the interaction and propagation of multimode cracks provide extrinsic toughening for SLCs.The pure Cu lamellae with low density grain boundaries and dislocations and no TiB_(2)particles provide a channel with little electron scattering for the rapid transport of carriers,thereby ensuring high electrical conductivity.
